neil mckay Posted July 16, 2013 Report Share Posted July 16, 2013 (edited) I have pinking problem timing etc ok can any one advise me of any suitable octane boosters to try Edited July 16, 2013 by neil mckay Quote Link to post Share on other sites
cmdr19 Posted July 16, 2013 Report Share Posted July 16, 2013 Neil, before any of that additive stuff, try running it on Shell V-power (Nitro or whatever else they're calling it this week) in and see if it makes a difference. Mike Quote Link to post Share on other sites
jean Posted July 16, 2013 Report Share Posted July 16, 2013 Neil, I think the given timing figure was correct for 5 star fuel in the 70th, but today it's not valid anymore. You might start retarding the ignition step by step and see what it gives. In fact combustion occurs before the piston reaches the top point. If you don't use a rolling road it's a question of trial and error. Someone might call me wrong Quote Link to post Share on other sites
Peter Cobbold Posted July 16, 2013 Report Share Posted July 16, 2013 Need more info. PI or carbs? when does it pink? has it started in this hot weather, was OK before? IMO boosters are last ditch - mixture and spark first. Quote Link to post Share on other sites
Alec Pringle Posted July 16, 2013 Report Share Posted July 16, 2013 The original fuel requirement for a CP PI engine was 100/101 octane leaded . . . . 98/99 octane unleaded will not cut the mustard on the original timing, so amend the timing accordingly. Bear in mind that distributor wear may be playing a part too, in which case it's one for Dissie Doc ! Cheers Alec Quote Link to post Share on other sites
WWT338J Posted July 17, 2013 Report Share Posted July 17, 2013 You can still buy the real stuff to mix with your petrol http://www.tetraboost.com/ David Quote Link to post Share on other sites
Alec Pringle Posted July 17, 2013 Report Share Posted July 17, 2013 Not the nicest stuff to deal with, tetraethyl lead in any sort of concentration requires to be treated with the utmost respect. H&S isn't exactly one of my great concerns, but there are a few exceptions - and I wouldn't be playing with TEL without gloves suit and mask, thanks a bunch. At a cost of 25p/litre or thereabouts, it's not a cheap solution either on top of £1.45/lt for super unleaded. £1.70/lt in total . . . . . Damn sight easier to tweak the dissie . . . . or use NF octane booster, which is one of the few such products that actually works, albeit you need rather more than the listed dosage. Not particularly nice stuff to have around either, but not in the TEL league. Cheers Alec Quote Link to post Share on other sites
Andy Moltu Posted July 17, 2013 Report Share Posted July 17, 2013 A lot of pinking is down to slack dizzy springs allowing too much low speed advance. It may be worth checking the "eyes" of the springs are a snug fit on the posts of the advance mechanism. Then gradually retard until the pinking stops. Quote Link to post Share on other sites
Velo-felo Posted July 17, 2013 Report Share Posted July 17, 2013 For what its worth, I think a few degrees retarded is a better option than using nasty chemicals. To be honest, if it is only a few degrees it won't make a jot of difference in performance to normal use anyway and will be kinder to an engine that maybe a little tired. I'm also not convinced that there is a need to worry about using lead replacement and unleaded fuels either in average mileages. Steve Quote Link to post Share on other sites
ChrisR-4A Posted July 17, 2013 Report Share Posted July 17, 2013 Moss do a pack of stronger springs for the centrifugal advance. Cheaper than a can of booster and very effective. Start with the first two thicker than what you have now and increase if necessary . Worked well for me on the 4 pot but I am sure the Dist Doc would do even better. Quote Link to post Share on other sites
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